On this page you'll find two input boxes. First one is for your text to be analyzed. In the second box you can enter a list of numbers. The text will be analyzed on many different aspects, including an analysis based on the numbers you entered. It will show for each number the character on that position in the text.
In addition two checkboxes are available, which are optional modifiers to the character counting system. The first checkbox will not count whitespace (spaces, tabs) as character. The second checkbox will eliminate all characters which are not alphanumeric characters (meaning all characters not in ranges A-Z, a-z, and 0-9, and not being whitespaces will be disregarded). In order to eliminate both, just tick twice!